1. Field of the Invention
The invention of this application pertains to the field of fertility monitoring. More particularly, the invention pertains to improved methods and apparatus for predicting and detecting ovulation in female mammals.
2. Description of the Related Art
Mammalian females become pregnant relatively rarely because they cannot conceive most of the time. Conception can occur only during a short period of several hours after the approximately once-monthly-produced egg becomes available for fertilization. In agricultural animals, such as cows, these cycles are shorter (approximately 3 weeks). In every case, unless the sperm reaches the egg at just the right time, fertilization and conception will not take place: the egg will deteriorate and be expelled. This occurs during menstrual bleeding in the human female.
Human conception is less than probable under the best of circumstances. A perfectly healthy young woman trying to become pregnant may go through three or four menstrual cycles before achieving pregnancy. The suspected reason for this is the relatively frequent failure of proper orchestration of the various hormonal stimuli and other processes that constitute the complex mechanism of menstrual cycle.
The process of the egg becoming available for fertilization involves the release of the egg ("ovum") from storage in the ovary. It is called ovulation. The process is under the control of a number of hormones released into blood circulation by glands in the brain as well as in the reproductive organs. The brain hormones, released by the pituitary gland, are the peptides luteinizing hormone and follicle stimulating hormone. The ovarian hormones are the steroids estrogen and progesterone. The varying levels of these hormones can be and have been measured in blood as well as in urine. Such varying levels of the sex hormones are called hormonal cyclic profiles because they describe endocrinologically the cycling of the female organism from the preparation of a new egg, through ovulation to its deterioration. A notable feature of the hormonal cyclic profiles is that they are rather flat in the preovulatory part of the cycle: no peaks appear there early enough, and so no useful warning of the forthcoming ovulation is provided by them.
For family planning or in animal husbandry, it is important to monitor the fertility status and its cyclical variations from infertile, through a few fertile hours, to infertile again. Determining the few fertile hours of the female is essential if pregnancy is desired, as is the case of the many infertile or subfertile couples desiring pregnancy but having difficulty achieving it. The same is of great economic significance to the agribusiness whose profitability depends on the efficiency with which it manages its a highly-priced individual animals, such as dairy or meat producing herds of animals to be bred at optimal time and minimal expense, whether using natural or artificial insemination in the process.
Fertility status monitoring is essential for family planning in the birth control sense, that is for the spacing of births or their complete prevention by the so-called natural family planning method (NFP). NFP is practiced in many parts of the world (such as among Catholic populations) even if the contraceptive pill has had a significant impact on the birth control practice in the United States and other industrial and developed countries. Health awareness including concerns about side effects of medications, about interfering with one's hormonal biochemistry and related issues mean that modern women may well be receptive to scientific family planning, that is fertility awareness assisted by a reliable scientific technique.
Over the years, a number of different approaches to fertility monitoring have been undertaken. The oldest is the basal body temperature method. This is no longer favored by the gynecological profession. Fertility specialists are now more in favor of endocrinology-based methods of ovulation detection.